Implementing an Operational Framework to Develop a Streamflow Duration Assessment Method: A Case Study from the Arid West United States.

Streamflow duration information underpins many management decisions. However, hydrologic data are rarely available where needed. Rapid streamflow duration assessment methods (SDAMs) classify reaches based on indicators that are measured in a single brief visit.

Isotope fractionation during precipitation of methamphetamine HCl and discrimination of seized forensic samples.

Methamphetamine is a widely abused illicit drug. Increasingly, studies have focused on stable isotope analysis by isotope ratio mass spectrometry (IRMS) to link samples of methamphetamine synthesized together or from the same source of precursor. For this reason, it is important to understand potential sources of isotope fractionation that could cause variability in forensic data sets.

Vibrational spectroscopy and quantum chemical studies of 1,6,7,12,13,18-hexaazatrinaphthylene and related compounds.

The spectral properties of 1,6,7,12,13,18-hexaazatrinaphthylene (HATN) and a number of related compounds are modeled using density functional theory, B3LYP. The calculations predict the frequencies with mean absolute deviation of 6 cm(-1) and there is little improvement on going to basis sets larger than 6-31 G(d). The substituent effects on the observed spectra are modeled effectively in both frequency shifts and relative intensities.